This invention relates to a flexible magnetic disc drive apparatus which comprises:
a door;
a disc clamper assembly for holding a flexible magnetic disc bored at the center (hereinafter referred to as "a disc") between the clamper assembly and a spindle;
a link mechanism for causing the door to be moved interlockingly with the clamper assembly and also the flexible magnetic disc to be held by the clamper assembly in accordance with the extent to which the door is moved; and
a housing for receiving said door, disc clamper assembly and link mechanism.
Flexible magnetic disc drive apparatuses are now widely accepted. This kind of apparatus has a mechanism allowing for the easy exchange of discs. This exchange mechanism is actuated interlockingly with a door opened or closed by the operator. The inner diameter of the disc is matched with that of a reference hole formed in the spindle and is fitted to the spindle with a prescribed clamping force. The above-mentioned mechanism is indicated in FIGS. 1 and 2. As shown in both figures, a disc 10 is clamped between a spindle 12 and clamper 14. The clamper 14 is rotatably supported and driven with the spindle 12 without mutual displacement due to a frictional force resulting from an axially-applied load. Even if it is initially inserted off-center from the spindle 12, the center of the disc 10 is eventually rendered concentric with the spindle 12 by the tapered portion of the clamper 14. A lever 20 is fitted near the backside 18 of a housing 16 in a state swingable around a pin 22. The left front end of said lever 20 is connected to a door 23. The lever 20 swings around the pin 22 in accordance with the extent to which the door 23 is operated. The clamper 14 is fitted to substantially the midpoint of the lever 20. When moved downward by the swinging of the lever, the clamper 14 is fitted into the reference hole 24 formed in the spindle 12. FIG. 2 indicates the relative positions of the clamper 14, the reference hole 24 of the spindle 12 and the disc 10 inserted into the housing 16, showing that the axis of the disc 10 is slightly displaced from that of the reference hole 24 toward the left side.
Description will now be given of the operation of the conventional flexible magnetic disc drive apparatus. When the door 23 is closed by means of the swinging of the lever 20, then the disc 10 is pushed rightward by the conical inclined plane 28 (with an indicated angle of inclination .theta.) formed in the lower part of the clamper 14, causing the center of the disc 10 to be aligned with that of the spindle 12. When the clamper 14 is moved further downward, the disc 10 is clamped between the clamper 14 and spindle 12. The total extent to which the clamper 14 is moved during the above-mentioned operation is equal to the sum of its movement for effecting centering between the disc 10 and spindle 12 by means of the descent of the inclined plane 28 and its subsequent movement for ensuring the tight clamping of the disc 10. When the disc 10 is fitted to the subject apparatus, the clamper 14 has to be moved to the above-mentioned extent. Since extensive movement of the clamper 14 enlarges the vertical measurement of the subject apparatus, it is preferred that the clamper 14 be moved as little as possible.
A flexible magnetic disc drive apparatus of the above-mentioned type is now widely accepted. Recently, however, both computers and their supporting hardware have been greatly reduced in size, and so the need to develop a thin and compact flexible magnetic disc drive apparatus has grown. When the industry sought to meet the above-mentioned requirements simply by miniaturizing the conventional magnetic disc drive apparatus of the aforementioned arrangement, the following drawbacks resulted. Since the clamper 14 had to be moved to a smaller extent, the inclination angle .theta. shown in FIG. 2 had to be enlarged, resulting in an inaccurate centering between the disc 10 and spindle 12; the edge of the central hole of the disc 10 also tended to be easily damaged; and since the space between the clamper 14 and spindle 12 was narrowed, the disc 10 readily struck against the outer end of the clamper 14. In addition, since a distance n (FIG. 1) between the pin 22 supporting the lever 20 and the point at which the clamper 14 was set in place was narrowed, the clamper 14 descended not linearly, but arcuately around the periphery of an imaginary circle centered at the pin 22;
The inclined plane 28 of the clamper 14 was forcefully fitted into the reference hole 24 of the spindle 12 by being moved obliquely down the inner peripheral wall of said reference hole 24. Difficulties were presented in effecting the clamping of the disc 10 and the centering between the disc 10 and spindle 12, and an attempt to minimize the above-mentioned drawbacks was accompanied by various other difficulties as well.
Studies were made to develop a new magnetic disc drive apparatus in order to eliminate the afore-mentioned drawbacks. With the various proposed magnetic disc drive apparatuses, the lever 20 extends fully from the front end to the rear end of the housing 16 along the central line of a space provided above the housing 16. Noticeable limitations are imposed on the arrangement of devices and members devised for any of the proposed magnetic disc drive apparatuses. To date, therefore, no satisfactory magnetic disc drive apparatus has been realized. The hatching of FIG. 3 indicates the approximate area 23a and 20a occupied by the door 23 and lever 20 as viewed from the top of the conventional flexible magnetic disc apparatus. It can be seen from FIG. 3 that the hatched area is quite large.